1 #ifndef __LINUX_PERCPU_H 2 #define __LINUX_PERCPU_H 3 4 #include <linux/preempt.h> 5 #include <linux/slab.h> /* For kmalloc() */ 6 #include <linux/smp.h> 7 #include <linux/cpumask.h> 8 #include <linux/pfn.h> 9 10 #include <asm/percpu.h> 11 12 /* enough to cover all DEFINE_PER_CPUs in modules */ 13 #ifdef CONFIG_MODULES 14 #define PERCPU_MODULE_RESERVE (8 << 10) 15 #else 16 #define PERCPU_MODULE_RESERVE 0 17 #endif 18 19 #ifndef PERCPU_ENOUGH_ROOM 20 #define PERCPU_ENOUGH_ROOM \ 21 (ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \ 22 PERCPU_MODULE_RESERVE) 23 #endif 24 25 /* 26 * Must be an lvalue. Since @var must be a simple identifier, 27 * we force a syntax error here if it isn't. 28 */ 29 #define get_cpu_var(var) (*({ \ 30 extern int simple_identifier_##var(void); \ 31 preempt_disable(); \ 32 &__get_cpu_var(var); })) 33 #define put_cpu_var(var) preempt_enable() 34 35 #ifdef CONFIG_SMP 36 37 #ifdef CONFIG_HAVE_DYNAMIC_PER_CPU_AREA 38 39 /* minimum unit size, also is the maximum supported allocation size */ 40 #define PCPU_MIN_UNIT_SIZE PFN_ALIGN(64 << 10) 41 42 /* 43 * PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy 44 * back on the first chunk for dynamic percpu allocation if arch is 45 * manually allocating and mapping it for faster access (as a part of 46 * large page mapping for example). 47 * 48 * The following values give between one and two pages of free space 49 * after typical minimal boot (2-way SMP, single disk and NIC) with 50 * both defconfig and a distro config on x86_64 and 32. More 51 * intelligent way to determine this would be nice. 52 */ 53 #if BITS_PER_LONG > 32 54 #define PERCPU_DYNAMIC_RESERVE (20 << 10) 55 #else 56 #define PERCPU_DYNAMIC_RESERVE (12 << 10) 57 #endif 58 59 extern void *pcpu_base_addr; 60 61 typedef struct page * (*pcpu_get_page_fn_t)(unsigned int cpu, int pageno); 62 typedef void (*pcpu_populate_pte_fn_t)(unsigned long addr); 63 64 extern size_t __init pcpu_setup_first_chunk(pcpu_get_page_fn_t get_page_fn, 65 size_t static_size, size_t reserved_size, 66 ssize_t dyn_size, ssize_t unit_size, 67 void *base_addr, 68 pcpu_populate_pte_fn_t populate_pte_fn); 69 70 extern ssize_t __init pcpu_embed_first_chunk( 71 size_t static_size, size_t reserved_size, 72 ssize_t dyn_size, ssize_t unit_size); 73 74 /* 75 * Use this to get to a cpu's version of the per-cpu object 76 * dynamically allocated. Non-atomic access to the current CPU's 77 * version should probably be combined with get_cpu()/put_cpu(). 78 */ 79 #define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu))) 80 81 extern void *__alloc_reserved_percpu(size_t size, size_t align); 82 83 #else /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ 84 85 struct percpu_data { 86 void *ptrs[1]; 87 }; 88 89 /* pointer disguising messes up the kmemleak objects tracking */ 90 #ifndef CONFIG_DEBUG_KMEMLEAK 91 #define __percpu_disguise(pdata) (struct percpu_data *)~(unsigned long)(pdata) 92 #else 93 #define __percpu_disguise(pdata) (struct percpu_data *)(pdata) 94 #endif 95 96 #define per_cpu_ptr(ptr, cpu) \ 97 ({ \ 98 struct percpu_data *__p = __percpu_disguise(ptr); \ 99 (__typeof__(ptr))__p->ptrs[(cpu)]; \ 100 }) 101 102 #endif /* CONFIG_HAVE_DYNAMIC_PER_CPU_AREA */ 103 104 extern void *__alloc_percpu(size_t size, size_t align); 105 extern void free_percpu(void *__pdata); 106 107 #else /* CONFIG_SMP */ 108 109 #define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); (ptr); }) 110 111 static inline void *__alloc_percpu(size_t size, size_t align) 112 { 113 /* 114 * Can't easily make larger alignment work with kmalloc. WARN 115 * on it. Larger alignment should only be used for module 116 * percpu sections on SMP for which this path isn't used. 117 */ 118 WARN_ON_ONCE(align > SMP_CACHE_BYTES); 119 return kzalloc(size, GFP_KERNEL); 120 } 121 122 static inline void free_percpu(void *p) 123 { 124 kfree(p); 125 } 126 127 #endif /* CONFIG_SMP */ 128 129 #define alloc_percpu(type) (type *)__alloc_percpu(sizeof(type), \ 130 __alignof__(type)) 131 132 /* 133 * Optional methods for optimized non-lvalue per-cpu variable access. 134 * 135 * @var can be a percpu variable or a field of it and its size should 136 * equal char, int or long. percpu_read() evaluates to a lvalue and 137 * all others to void. 138 * 139 * These operations are guaranteed to be atomic w.r.t. preemption. 140 * The generic versions use plain get/put_cpu_var(). Archs are 141 * encouraged to implement single-instruction alternatives which don't 142 * require preemption protection. 143 */ 144 #ifndef percpu_read 145 # define percpu_read(var) \ 146 ({ \ 147 typeof(per_cpu_var(var)) __tmp_var__; \ 148 __tmp_var__ = get_cpu_var(var); \ 149 put_cpu_var(var); \ 150 __tmp_var__; \ 151 }) 152 #endif 153 154 #define __percpu_generic_to_op(var, val, op) \ 155 do { \ 156 get_cpu_var(var) op val; \ 157 put_cpu_var(var); \ 158 } while (0) 159 160 #ifndef percpu_write 161 # define percpu_write(var, val) __percpu_generic_to_op(var, (val), =) 162 #endif 163 164 #ifndef percpu_add 165 # define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=) 166 #endif 167 168 #ifndef percpu_sub 169 # define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=) 170 #endif 171 172 #ifndef percpu_and 173 # define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=) 174 #endif 175 176 #ifndef percpu_or 177 # define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=) 178 #endif 179 180 #ifndef percpu_xor 181 # define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=) 182 #endif 183 184 #endif /* __LINUX_PERCPU_H */ 185